RESUMO
OBJECTIVE: To report a case of drug-induced hepatitis associated with low-dose venlafaxine. CASE SUMMARY: A 60-year-old white woman receiving venlafaxine 75 mg daily for vasomotor symptoms presented after one month of therapy with nonspecific complaints, including abdominal pain. A series of diagnostic and laboratory tests revealed an enlarged liver and elevated alanine aminotransferase (ALT) up to 372 U/L, aspartate aminotransferase (AST) up to 99 U/L, gamma-glutamyltransferase (GGT) up to 962 U/L, and alkaline phosphatase up to 758 U/L. All potential hepatotoxic medications were discontinued. Within one week after stopping venlafaxine, her liver function test results showed marked improvement. Almost 4 weeks after discontinuing therapy, venlafaxine 37.5 mg was reinitiated. Her ALT, AST, GGT, and alkaline phosphatase again increased to 269, 49, 256, and 263 U/L, respectively, 6 days after resuming therapy. Upon discontinuation of venlafaxine, her liver function abnormalities resolved. DISCUSSION: This case is significant due to the severity of symptoms and consequent liver function test results involved in diagnosing drug-induced hepatitis. It is also remarkable because of the hepatotoxicity that occurred initially and on rechallenge with low-dose venlafaxine. The hepatotoxic effects of venlafaxine have been characterized as rare and idiosyncratic. The Naranjo probability scale revealed that the adverse drug event was probable. CONCLUSIONS: Venlafaxine therapy can lead to drug-induced hepatitis, even when used at low doses. Clinicians should be aware of this possible adverse effect of venlafaxine therapy and monitor patients closely after initiation of therapy.